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There are basically three types of DC Motors based upon the connections of field and armature winding. First is DC Series Motor, second is DC Shunt motor and third is DC Compound motor. DC Motors require to have DC power supply. But providing high voltage power supply directly from the batteries would not be possible in number of cases. So a rectifier circuit is used, which converts the AC power into DC. And then this DC power is given to the DC Motor.  We had done the connections for powering the DC Series motor. We had 220V DC Series Motor rated 4.2 Amps.  This motor have 4 wires, 2 of the wires are for Armature winding and remaining 2 are for the field winding. Lets see the wiring diagram for the this motor. The connections are done as per the circuit diagram as shown above. We first check the continuity of the same type of wires using multimeter. Then make common connection within one of the armature wire terminal with one of the field winding terminal. Remaining one termi...

  How do we generally measure length of any object? Let us suppose we are having a small rod and cm scale as shown: If we ask you what is the length of the rod you would say it is somewhere between 2.1 cm and 2.2 cm and for general practical purpose we would treat it to be 2.2 cm, as it seems somewhat closer to 2.2 cm. Here the smallest measurement which can be made is 0.1 cm, this is nothing but the Least Count (L.C.) of this centimeter scale. So we here infer that if our object lies between two successive markings as in above case, we won’t be able to correctly define its length. When we deal with experiments where accuracy up to 2 nd decimal(as in cm) is required, using this normal scale won’t be a great idea!  This is where Vernier Caliper  comes into the picture. This length measuring instrument was invented by Pierre Vernier the French Mathematician in 1631. The regular vernier caliper allow us to find length up to 2 nd decimal (as in cm) without actually need...